Optical transmission module and optical communication system using the same

Abstract

A beam spot size enlarger waveguide for enlarging the beam spot size is connected to a beam spot size reducer waveguide for shrinking the beam spot size, along with the direction of the propagation of light beam; or the beam spot size enlarger waveguide, a beam spot size maintainer waveguide for maintaining the beam spot size constantly, and the beam spot size reducer waveguide are connected in the direction of the propagation of light beam.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an optical transmitter module used primarily in an optical transmission system or in an optical switching system (both referred to as an optical communication system) and more particularly to an optical connecting technology used for connecting a light emitting or receiving element with optical fibers in the optical transmission module, or a light emitting or receiving element with an optical circuit, as well as an optical circuit with optical fibers.[0003]2. Description of the Prior Art[0004]Construction of communication lines using optical fibers is projected not only among office buildings of a variety of industries but also among condominiums and residences, as the optical technology of communication develops. One of problems concerned is the cost of the optical transmission system, in particular the rate of lowering the cost of optical modules that reach to the subscribers. In the p...

AI Technical Summary

Benefits of technology

[0013]Therefore a primary object of the present invention is to provide an optical transmission module and an optical communication system allowing the coupling efficiency between optical components to be improved.

[0014]A secondary object of the present invention is to provide an optical transmission module and an optical communication system which may improve at least one of either the coupling efficiency or the tolerance between optical components.

[0018]In order to achieve the secondary object described above, the present invention comprises: a first optical waveguide for enlarging the spot size of an optical beam in the direction of propagation of the beam; a second optical waveguide for maintaining the beam spot size of optical beam enlarged by the first optical waveguide; and a third optical waveguide for shrinking the beam spot size of optical beam maintained by the second waveguide.

Problems solved by technology

One of problems concerned is the cost of the optical transmission system, in particular the rate of lowering the cost of optical modules that reach to the subscribers.

This approach of providing a lens between an optical element and a waveguide has many drawbacks, for lowering the cost of optical modules for subscribers, such as increased number of parts, alignment required between three independent members, and consequently a complex work to mate them.

As a consequence the conventional laser system has an insufficient yield, which pushed up the price of laser elements and finally a considerable reduction of cost of the optical modules is not yet achieved.

However, this solution may result in an increase of the number of parts and a complex method of production so that the achievement of lowering cost of optical modules will be difficult.

Images